UV excimer laser ablation

The requirements of thin-film ferroelectrics are stoichiometry, phase formation, crystallization, and microstmctural development for the various device appHcations. As of this writing multimagnetron sputtering (MMS) (56), multiion beam-reactive sputter (MIBERS) deposition (57), uv-excimer laser ablation (58), and electron cyclotron resonance (ECR) plasma-assisted growth (59) are the latest ferroelectric thin-film growth processes to satisfy the requirements. 

Bovine carotid artery endothelial cells UV excimer laser ablation to open polyacrylamide coating, protein backfill 2005 [102]... 

Iwanaga S, Akiyama Y, Kikuchi A et al (2005) Fabrication of a cell array on ultrathin hydrophilic polymer gels utilising electron beam irradiation and UV excimer laser ablation. Biomaterials 26(26) 5395-5404... 

Plastic materials have gained importance in microfabrication due to their ease of molding, inexpensiveness, and disposability. Some workers have used these substrates for fabrication of microchips. Pethig et al. [78] and Roberts et al. [79] used laser ablation as a direct method for creating microchannels in plastic chips without the need for fabrication. The methods used an UV excimer laser to bum the microchannels onto the polymer substrate, moving in a predefined,... 

An excimer laser was also used to machine a PC chip (6 mm thick) to create 160-pm-wide channels (60 pm deep), [811] or on a polyimide sheet [192,811]. Another UV excimer laser (248 nm) was used to ablate microstructures within PC channels (fabricated by imprinting) [193]. 

Another important feature of ablation, which is never discussed in the photothermal models was repeatedly emphasized by Srinivasan [92] the products of pyrolysis or ablation with a CO2 laser are very different to the products of excimer laser ablation in the UV. This suggests that different processes take place between pyrolysis (thermal decomposition) and UV laser ablation. 

LIBS/RELMA was tested on a series of industrial NBR compounds with various deliberate recipe errors of all components (rubber, fillers, carbon-black, plasticisers, FRs, AOs, accelerators, ZnO, sulfur, mineral oil). UV excimer laser wavelengths must be employed on polymeric surfaces since only then sharp and regular ablation patterns are produced without any thermal side-effects (at variance with IR NdiYAG). LIBS/RELMA can be used for off-line analysis of vulcanisates, homogeneity testing and particle analysis in mixtures and element analysis of raw materials (in particular for fillers). RELMA... 

The performance of ablation lasers depends largely on two factors, namely the nominal laser wavelength and intensity, and whether the continuous or pulsed mode of irradiation is used. Studies on the first two factors have yielded controversial results that can be ascribed to differences in sample nature or grain size. Thus, ruby (694 nm), Nd YAG (1064, 532, 266 and, recently, 213 nm) and excimer (308, 248, 222, 193 and, recently, 157 nm) lasers have been used for laser ablation (LA). A comparison of the Nd YAG laser operating at 1064 nm and 266 nm revealed better absorption of UV wavelength by most types of samples and also decreased fractionation. The particle sizes produced during ablation were smaller with 266 than with 1064 nm, which was possibly the reason for the reduced... 

The photochemical decomposition process occurs exclusively at UV wavelengths with excimer lasers, such as XeCl (308 nm), KrF (248 nm), and ArF (193 nm). The laser pulse duration has much less effect on ablation. Long pulses of laser irradiation of the order of microseconds can still cause polymer ablation. However, there is a threshold fluence (mJ/cm ) above which the ablation oeexus. The threshold fluence is different for different polymers, for different photon wavelengths, and for different pulse durations [5]. 

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